28181716993 has 2 divisors, whose sum is σ = 28181716994. Its totient is φ = 28181716992.

The previous prime is 28181716967. The next prime is 28181717017. The reversal of 28181716993 is 39961718182.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26480401984 + 1701315009 = 162728^2 + 41247^2 .

It is a cyclic number.

It is not a de Polignac number, because 28181716993 - 2¹⁷ = 28181585921 is a prime.

It is not a weakly prime, because it can be changed into another prime (28181716903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14090858496 + 14090858497.

It is an arithmetic number, because the mean of its divisors is an integer number (14090858497).

Almost surely, 2^28181716993 is an apocalyptic number.

It is an amenable number.

28181716993 is a deficient number, since it is larger than the sum of its proper divisors (1).

28181716993 is an equidigital number, since it uses as much as digits as its factorization.

28181716993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 55.

The spelling of 28181716993 in words is "twenty-eight billion, one hundred eighty-one million, seven hundred sixteen thousand, nine hundred ninety-three".